Helichrysum arenarium (L) Moench (sandy everlasting) is a valuable plant for therapy, having multiple applications in traditional medicine, applications which are confirmed nowadays by science. The main polyphenols found in sandy everlasting flowers were shown to have antioxidant and UVscreen effects. In order to expand our knowledge concerning the synergistic therapeutic effects of the polyphenols from Helichrysum arenarium (L) flowers, an extract was prepared using 50% ethanol as extraction phase, followed by the removing of ethanol using a Royeyov IKA RV10 rotary evaporator. The chemical analysis of the extract consisted in the assessment of total polyphenol content (Folin-Ciocalteu) and flavonoid fingerprint (high-performance thin-layer chromatography -HPTLC). For the polyphenolic extract there were assessed the antioxidant activity (measured by two methods: ferric reducing antioxidant power (FRAP) and radical scavenging activity with DPPH)) and sun protection factor (SPF) (assessed using an in vitro spectrometric method). Furthermore, the cytotoxic and antitumor effects were evaluated on two cell lines: pMSCs (palatal mesenchymal stem cells) and HeLa (ATTC® CCL-2™) cell line (epithelial cells derived from human cervical adenocarcinoma). The extract contains apigenin-7-glucoside, luteolin-7-glucoside and rosmarinic acid. The extract shows a significant UV-screen protection effect, particularly for UVB radiations. The extract has not cytotoxic effects on palatal mesenchymal stem cells. The cytometric apoptosis assay on HeLa cell line reveals the in vitro antitumor effect of the extract. The results highlights both antioxidant and antitumor activity as well as the UV-screen effect of the polyphenols from Helichrysum arenarium flowers. All these data not only confirm the high antioxidant properties of the polyphenols contained in the sandy everlasting flowers, but also open new ways of applications for therapy of this plant.